netem: remove unnecessary 64 bit modulus

Fix compilation on 32 bit platforms (where doing modulus operation
with 64 bit requires extra glibc functions) by truncation.
The jitter for table distribution is limited to a 32 bit value
because random numbers are scaled as 32 bit value.

Also fix some whitespace.

Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in nanoseconds")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 644323d6081cf58a37d173a39844baf97bd8b87d..dd70924cbcdfe4d078f05d346cacf83abb1a9f2e 100644 (file)
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -312,9 +312,9 @@ static bool loss_event(struct netem_sched_data *q)
  * std deviation sigma.  Uses table lookup to approximate the desired
  * distribution, and a uniformly-distributed pseudo-random source.
  */
-static s64 tabledist(s64 mu, s64 sigma,
+static s64 tabledist(s64 mu, s32 sigma,
                     struct crndstate *state,
-                        const struct disttable *dist)
+                    const struct disttable *dist)
 {
        s64 x;
        long t;
@@ -327,7 +327,7 @@ static s64 tabledist(s64 mu, s64 sigma,
 
        /* default uniform distribution */
        if (dist == NULL)
-               return (rnd % (2*sigma)) - sigma + mu;
+               return (rnd % (2 * sigma)) - sigma + mu;
 
        t = dist->table[rnd % dist->size];
        x = (sigma % NETEM_DIST_SCALE) * t;